The coral gardens of the earth are fascinating miracle of nature, and form key elements in the complex of life communities in the oceans. Builder of the delicate underwater worlds are little ones: The lime to be the work of myriads of small coral polyps catch with their delicate Arms Plankton skeletons. Many coral species feed but in addition due to a symbiosis with algae. The single-cell life in the body of the cnidarians and win it from the sun’s light energy. Of the formed carbon compounds give the polyps a little and get from you in return, everything else you need to live.
A spooky spectacle
In the so-called coral bleaching, the destruction of this partnership is reflected: If the algae are affected by high water temperatures or other stress factors, leaving the coral polyps. As a result, the white limestone skeleton of the coral begins to seem more and more through its transparent tissue hindurchzu. If this process is strong and long lasting, die, the coral polyps eventually and it was only the bleach “bone stay” left. The coral bleaching sets now becoming more common as a shroud over the reefs of the earth, warn researchers. Blame it on the rising water temperatures are in the Wake of global warming.
The coral die is researchers, however, still some puzzles. A mysterious phenomenon is an amazing color development, the scientists have found in some of the bleaching affected Coral populations: to lose Instead of their normal color increasingly, these coral various intense colors. This effect have now been dedicated to the researchers working with Jörg wiedenmann from the University of Southampton a study. They have carried out a series of experiments in aquariums. They exposed the coral to different stress factors, as you go also in the nature of bleaching, in advance, in order to examine when the phenomenon occurs. Then, they analyzed the pigments, the color reactions are based.
to report A sun protection for the sensitive Partner
As, it is clear from their results that the phenomenon in corals that have experienced, in contrast to extreme damage to more episodes of mild or short-sea warming, or other disturbances. The polyps react with the formation of the color pigments. According to the researchers, it is, apparently, a light protection, to prevent additional stress for the algae and you may be able to return, encouraged. “In healthy corals, a large part of the sun is absorbed light by the photosynthetic pigments of the algal symbionts. If the corals lose their symbionts, the light is reflected, however, increasingly from the white coral skeleton in the tissue of the polyps,“ explained Wiedenmann. This effect thus increases the internal light level and is for the symbiote to be very stressful. It can therefore affect their living conditions and their return to the normalization of the conditions delay, or even prevent, the scientists say.
If the coral cells have, however, in spite of the environmental stress that caused the Bleaching, some of your normal abilities, you can make the light protection of pigments. If you can recover this then the algae population and the symbionts use the light for their photosynthesis, the excessive radiation Inside the coral polyps and the cells reduce the production of colored pigments to normal levels, the scientists explain.
It is, therefore, an encouraging sign, if it is in a damaged reef suddenly colorful. Wiedenmann and his colleagues report in this context of current observations: During the large-scale coral Barrier Reef in March, bleach in some areas of the Great-April 2020 have occurred in some areas of the colored phenomena. Thus, the hope that at least some patches of the largest reef system in the world, prospects for Recovery, say the scientists. They emphasize, however, that ultimately, only a significant reduction in greenhouse gases on a global level and a sustainable improvement of the water quality at the regional level, the coral reefs can save.
source: University of Southampton, technical article: Current Biology, doi: 10.1016/j. cub.2020.04.055
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